The present invention relates to a device for limiting the lowering of an implement on a working vehicle.
In some working vehicles, an implement is coupled to a vehicle body via a link mechanism such that the implement can be raised and lowered, and the lowering of the implement is performed using the weight of the implement itself. Such a working vehicle is provided with a lowering limiting device for limiting the lowering of the implement under its own weight by bringing an abutting member, which moves in tandem with the raising and lowering movement of the implement, into contact with an abutted member provided in the vehicle body when the implement is lowered.
In an example of the device for limiting the lowering of an implement on a working vehicle as described above, a stopper member in which plural abutted portions are formed in a line in the shape of a spiral staircase is provided as the abutted member, and a lowering limit position of a mower, which is an example of the implement, is changed to an arbitrary vertical position for mowing (vertical position for work) or a vertical position for travel/transport by rotating this stopper member (see JP 2004-236641A, for example).
With the above-described configuration, when the working vehicle is shifted from a working state to a travelling state, the implement is raised to an upper limit position by a raising and lowering device, and then the abutted member is rotated while the operational state of the abutted member is checked so that the abutted portion of the abutted member (the stopper member) with which the abutting member makes contact is changed from an abutted portion corresponding to an arbitrary vertical position for work to an abutted portion corresponding to the vertical position for travel/transport near the upper limit. Thus, the lowering limit position of the implement can be changed from the arbitrary vertical position for work to the vertical position for travel/transport, and the implement can be prevented from lowering from the vertical position for travel/transport.
When the working vehicle is shifted from the travelling state to the working state, the implement is raised to the upper limit position by the raising and lowering device, and then the abutted member is rotated while the operational state of the abutted member is checked so that the abutted portion of the abutted member with which the abutting member makes contact is changed from the abutted portion corresponding to the vertical position for travel/transport to an abutted portion corresponding to an arbitrary vertical position for work. Thus, the lowering limit position of the implement can be changed from the vertical position for travel/transport to the arbitrary vertical position for work, and the implement can be prevented from lowering from the arbitrary vertical position for work.
That is to say, every time the lowering limit position of the implement is changed between an arbitrary vertical position for work and the vertical position for travel/transport, it is necessary to rotate the abutted member while checking the operational state of the abutted member. For this reason, there is room for improvement in increasing the operability.
Moreover, since the abutted member has the plural abutted portions formed in a line in the shape of a spiral staircase, the larger the distance between an arbitrary vertical position for work and the vertical position for travel/transport is, the more time the operation of rotating the abutted member takes.